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Aditya L-1 Mission

Description

Aditya L-1 Mission

Introduction

Aditya-L1 is the first space based observatory class Indian solar mission to study the Sun from a substantial distance of 1.5 million kilometers. 

The solar probe was transported into space using the Polar Satellite Launch Vehicle (PSLV) in the 'XL' configuration. Initially, the PSLV will position the Aditya L-1 in a lower Earth orbit.

Afterward, both the spacecraft's orbit and its speed around Earth will be increased using onboard propulsion until it is catapulted towards the Sun.

Ultimately, the spacecraft will be placed into a halo orbit around Lagrange point 1 (L1) within the Sun-Earth system, located approximately 1.5 million km from Earth.

Named after the rising Sun, the Aditya L-1 will complete its journey to the L1 point in approximately four months. On its mission, the spacecraft will carry seven instruments to observe solar activities for a duration of five years.


The spacecraft will carry seven payloads to observe solar activities for five years. 

    • Visible Emission Line Coronagraph (VLEC) 
    • Solar Ultraviolet Imaging Telescope (SUIT) 
    • Solar Low Energy X-ray Spectrometer (SoLEXS) 
    • High Energy L1 Orbiting X-ray Spectrometer (HEL1OS) 
    • Aditya Solar wind Particle Experiment (ASPEX) 
    • Plasma Analyser Packages for Aditya (PAPA) 

Goals of the Aditya L-1 Mission

·         To enhance our understanding of the Sun and its impact on us, including its radiation, heat, particle flow, and magnetic fields.

·         To examine the Sun's upper atmospheric layers, known as the chromosphere and corona. The corona represents the outermost layer, while the chromosphere lies just beneath it.

  • To examine coronal mass ejections (CMEs), which are large expulsions of plasma and magnetic fields from the Sun’s corona.
  • To analyse the corona’s magnetic field and the driver of the space weather.
  • To understand why the Sun’s not-so-bright corona is a million degree Celsius hot when the temperature on the surface of the Sun is just about 5,500 degree Celsius.
  • To help scientists know the reasons behind the acceleration of particles on the Sun, which leads to the solar wind — the constant flow of particles from the Sun


What is Space Weather?

Space weather encompasses the shifting environmental conditions in space, primarily shaped by activities taking place on the surface of the Sun. These conditions involve the solar wind, magnetic fields, and solar events such as Coronal Mass Ejections (CMEs).

These events lead to alterations in the magnetic field and charged particle environment close to celestial bodies. In the case of Earth, the interaction between its magnetic field and the field carried by CMEs can induce magnetic disturbances near our planet, impacting the functioning of space assets.

What is Lagrange Points?

Lagrange points, designated as L1 to L5, exist in the space between any two celestial bodies.

These positions are where the gravitational pull of the celestial bodies balances with the centripetal force required to maintain a smaller third body in orbit. NASA describes these points as potential "parking spots" for spacecraft, allowing them to maintain a stable position in space with minimal fuel consumption.

They are named after the Italian-French mathematician Joseph-Louis Lagrange (1736-1813), who first identified these positions.

Among the five Lagrange points, three (L1, L2, and L3) are unstable, while the other two (L4 and L5) are stable. The stable points, L4 and L5, are also known as Trojan points and are sometimes inhabited by celestial bodies like asteroids.

What is Halo Orbit?

NASA explains that a spacecraft can "orbit" around an unstable Lagrange point with minimal use of thrusters for stationkeeping.

This unique orbit is referred to as a halo orbit because it resembles an ellipse suspended above a celestial body. It's important to note that an unstable Lagrange point does not exert any attractive force on its own.

Why Probe Orbits L1?

The reason the probe orbits L1 is because this point provides a continuous and unobstructed view of the Sun.

L2 is located behind Earth and obstructs the Sun's view, while L3 is positioned behind the Sun, making it less suitable for communication with Earth.

Although L4 and L5 are stable locations, they are significantly farther from Earth compared to L1, which is situated directly between the Sun and Earth.

What is Solar and Heliospheric Observatory?

The European Space Agency's (ESA) Solar and Heliospheric Observatory spacecraft (SOHO) is also situated in a halo orbit around L1 in the Earth-Sun system.

 This spacecraft has been operational since 1996 and has made significant discoveries, including more than 400 comets, the study of the Sun's outer layers, and the examination of solar winds.

Why Study the Sun from Space?

The Sun emits radiation, energetic particles, and magnetic fields. However, Earth's atmosphere and magnetic field act as protective shields, blocking many harmful radiations.

This means that studying the Sun from Earth alone cannot provide a comprehensive understanding, making observations from space, beyond Earth's atmosphere, essential.

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